The primary mechanisms leading to myocardial cell death following ischemic insult are not known. A number of reports have shown early changes in mitochondrial ATP synthesis and calcium transport kinetics during ischemic heart damage. A new method will be utilized to produce depletion of internal adenine nucleotides to alter calcium kinetics in normal heart mitochondria. Changes in the mechanisms governing inorganic phosphate transport through the mitochondrial inner membrane will be explored as a possible primary cause of altered mitochondrial function in cardiac ischemia. Specifically, the inhibition of adenine and calcium transport by acyl CoA esters and the subsequent damage of the mitochondrial inner membrane will be studied. Spectrophotometric techniques will be used to monitor mitochondrial calcium transport and swelling-contraction of the mitochondrial inner membrane compartment. Multi-parameter measurements (oxygen and hydrogen electrode) in conjunction with the above mentioned techniques will be employed to gain an integrated picture of mitochondrial function from normal and ischemic hearts. Fluorometric techniques will be used for adenine nucleotide determinations and possible separate movements of calcium in the lipid phase of the mitochondrial membrane. An understanding of the fundamental changes occurring in the cellular compartments of the ischemic heart can subsequently be utilized to develop rational therapeutic interventions to reduce myocardial damage during ischemic insult.